<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>选择器</title>
    <style>
        /*id选择器*/
        #p1{color:red}
        /* 类选择器*/
        .c1{color:blue}
        /* 分组选择器*/
        #p1,.c1,h3{background-color: yellow}
        /* 属性选择器*/
        input[type='text']{background-color: green}
        /* 任意元素选择器*/
        *{border: 1px solid red}
    </style>
</head>
<body>
    <input type="text"><input type="password">
    <p id="p1">悟空</p><p>八戒</p><p class="c1">沙僧</p>
    <div>苹果</div><div>香蕉</div><div class="c1">橘子</div>
    <h3>这是h3</h3>
</body>
</html>